The invention belongs to the field of environment technology and particularly relates to a method for effectively reducing the chemical oxygen demand (COD) of agricultural kaolin. The method for effectively reducing the COD of agricultural kaolin is characterized by comprising the following steps that: 1), kaolin, calcium hypochlorite and sodium peroxide according to a mass ratio of 100:(1-2):(1-5) are put into a mixing machine to be sealed, stirred and mixed to obtain a uniform powder mixture; 2), water is sprayed into the powder mixture according to a mass ratio of the powder mixture to thewater to be 100:(8-12), the fast stirring and mixing is carried out for 20 to 30 minutes so that the powder mixture and the water are subjected to full reaction, and samples after mixing reaction areobtained; and 3) the samples after the mixing reaction are taken out for packaging, and kaolin (products) for fertilizer carriers is obtained. The method effectively reduces the COD in the agricultural kaolin.